Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, for example. As technology has progressed, the demand for smaller semiconductor devices with improved performance has increased. As feature densities increase, widths of conductive lines and spacing between the conductive lines of back-end of line (BEOL) interconnect structures also need to be scaled smaller.
In order to meet these demands, a move away from the traditional materials used in the past is being made in semiconductor device design. To reduce an RC time delay, low dielectric constant (low-k) materials are being used as insulating materials, and there is a switch being made to use copper, rather than aluminum, as an interconnect material. The advantages of using copper for semiconductor device interconnects include the ability to operate faster and to manufacture thinner conductive lines, because copper has lower resistivity and better electromigration resistance compared to aluminum. Combining copper interconnects with low-k dielectric materials increases interconnect speeds by reducing the RC time delay.